There are 25 pigs and 12 chickens. This is the answer because pigs each have four legs, while chickens have two legs. This problem can be set up by a system of equations to easily find the answer:
x + y = 37; 4x + 2y = 124
To save time, the answer to this system of equations is x = 25, and y = 12. Because pigs have four legs, this means there are 25 pigs (as represented in the system of equations) and there are 12 chickens because they each have two legs.
Your final answer: There are 25 pigs and 12 chickens.